Errors in writing, voluntary changes by the bearers, modifications for language reasons... There are many reasons why the surname Uengtrakoolchai may have undergone changes or modifications, and from those modifications, surnames similar to Uengtrakoolchai may have appeared, as we can see.
Discerning whether the surname Uengtrakoolchai or any of the surnames similar to Uengtrakoolchai came first is not always easy. There are many reasons that could have led to the surname Uengtrakoolchai being written or pronounced differently, giving rise to a new, different surname Uengtrakoolchai with a common root.